Rehtona is a 2D puzzle-platformer developed by Chinese studio Dot 4 Joy. It was originally released on Steam on January 23, 2019. The mobile version, featuring additional content, was released on the App Store on September 19, 2019, as well as on Google Play on January 17, 2020.
The player controls Rehtona, a girl who can switch between Light and Dark worlds, as well as create "illusions". Each puzzle is a single level where the primary objective is to collect the jigsaw puzzle piece, and then meet Rehtona's companion Musii in the Dark world. The Dark world is only accessible through a locked gate, which can be opened with a key. Various obstacles may block the path to the key and/or to the puzzle piece, and the player has to figure out the way to clear them by pushing different types of boxes and activating switches.
The Light and Dark worlds mirror each other, but also have significant differences. Any change that happens in one world will affect the other. Some objects behave differently in each world - for example, Rehtona's "illusions" can only be created in the Light world, and become solid "statues" in the Dark world, which the player can then use as platforms.